Add runtime UV protection toggle and treat near-zero sense as external power.

Per-pod NVS enable (default off) via UART/ESP-NOW/dashboard, and skip UV latch when LiPo ADC reads ~0 mV so USB/external supply still boots.

Co-authored-by: Cursor <cursoragent@cursor.com>

main/pod_settings.c

@@ -9,6 +9,7 @@ static const char *TAG = "[SETTINGS]";
 static const char *NS = "powerpod";
 static const char *KEY_ACCEL_DZ = "accel_dz";
 static const char *KEY_UV_LATCH = "uv_latch";
+static const char *KEY_UV_EN = "uv_en";
 static const char *KEY_TAP_CFG = "tap_cfg";
 static const char *KEY_ID_MAP = "id_map";
 static const char *KEY_ID_BIND = "id_bind";
@@ -325,6 +326,58 @@ esp_err_t pod_settings_clear_uv_latched(void) {
   return pod_settings_set_uv_latched(false);
 }
 
+bool pod_settings_is_uv_enabled(void) {
+  if (!s_nvs_ready) {
+    return false;
+  }
+
+  nvs_handle_t handle;
+  esp_err_t err = nvs_open(NS, NVS_READONLY, &handle);
+  if (err != ESP_OK) {
+    return false;
+  }
+
+  uint8_t value = 0;
+  err = nvs_get_u8(handle, KEY_UV_EN, &value);
+  nvs_close(handle);
+
+  if (err == ESP_ERR_NVS_NOT_FOUND) {
+    return false;
+  }
+  if (err != ESP_OK) {
+    return false;
+  }
+  return value != 0;
+}
+
+esp_err_t pod_settings_set_uv_enabled(bool enabled) {
+  esp_err_t err = ensure_nvs();
+  if (err != ESP_OK) {
+    return err;
+  }
+
+  nvs_handle_t handle;
+  err = nvs_open(NS, NVS_READWRITE, &handle);
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "nvs_open failed: %s", esp_err_to_name(err));
+    return err;
+  }
+
+  err = nvs_set_u8(handle, KEY_UV_EN, enabled ? 1u : 0u);
+  if (err == ESP_OK) {
+    err = nvs_commit(handle);
+  }
+  nvs_close(handle);
+
+  if (err != ESP_OK) {
+    ESP_LOGE(TAG, "save uv_en failed: %s", esp_err_to_name(err));
+    return err;
+  }
+
+  ESP_LOGI(TAG, "UV protection %s", enabled ? "enabled" : "disabled");
+  return ESP_OK;
+}
+
 esp_err_t pod_settings_load_id_map(pod_id_map_t *out) {
   if (out == NULL) {
     return ESP_ERR_INVALID_ARG;